The bortezomib and bendamustine will be given using an intravenous line (IV) on days 1 and 4 of each cycle, with bortezomib being given first, before each dose of bendamustine. Each cycle will be 28 days long, so patients will be treated the first week of each cycle and then have 3 weeks 'off' (without any treatment). Disease assessments will be performed on day 22 of each cycle. Patients will receive the study drugs until their disease progresses or they are withdrawn from the study.